1. Write each number as a power of \(10\): \(100{,}000\), \(10{,}000{,}000\), and one billion.
2. Find the value of \(7 \times 10^4 + 3 \times 10^2\).
3. The average distance from Earth to the Sun is about \(150\) million kilometers. Write this distance in the form \(a \times 10^n\), where \(a\) is a whole number with no trailing zeros.
Hints
- Count the zeros in each number.
- Relate the number of zeros to the exponent in a power of \(10\).
- Evaluate each term in the sum before adding.
- In part 3, move all trailing zeros into the power of \(10\).
Solution
1. Count the zeros in each power of \(10\): \(100{,}000 = 10^5\), \(10{,}000{,}000 = 10^7\), and \(1{,}000{,}000{,}000 = 10^9\).
2. \(7 \times 10^4 = 70{,}000\) and \(3 \times 10^2 = 300\). Therefore, \(70{,}000 + 300 = 70{,}300\).
3. Since \(150\) million kilometers is \(150{,}000{,}000\,\text{km}\), removing the trailing zeros gives \(150{,}000{,}000 = 15 \times 10^7\).
Answer
1. \(10^5\), \(10^7\), and \(10^9\).
2. \(70{,}300\).
3. \(15 \times 10^7\,\text{km}\).